Fuel additive composition to improve fuel lubricity

ABSTRACT

The present disclosure relates to fuel additive compositions comprising one or more hydrogen bonding compounds derived from a long chain fatty acid, and one or more esters of a second long chain fatty acid. Such fuel additives improve the lubricity of the fuel.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a continuation application of U.S. patent application Ser. No.12/263,749 filed Nov. 3, 2008, now allowed, which claims priority toU.S. provisional application No. 60/984,501 filed Nov. 1, 2007, nowexpired, each of which is incorporated by reference.

FIELD

Described herein are fuel additive compositions that improve the fuellubricity and ignition properties of liquid petroleum distillate fuels.

BACKGROUND

As environmental legislation in the United States and Canada hasrequired that the sulfur content of diesel fuel be less than 15 ppm, thereduction in the sulfur content of diesel fuel has resulted in lubricityproblems. It has become generally accepted that the reduction in sulfuris also accompanied by a reduction in polar oxygenated compounds andpolycyclic aromatics, including nitrogen containing compounds, which isresponsible for the reduced boundary lubricating ability of severelyrefined (low sulfur) fuels. While low sulfur content does not in itselfcause lubricity problems, it has become the measure of the degree ofrefinement of the fuel, and this reflects the level of the removal ofpolar oxygenated compounds and polycyclic aromatics includingnitrogen-containing compounds.

It has been found that low sulfur diesel fuels increase the slidingadhesive wear and fretting wear of pump components such as rollers, camplate, coupling, lever joints and shaft drive journal bearings.

Nevertheless, concern for the environment has resulted in moves tosignificantly reduce the noxious components in emissions when fuel oilsare burnt, particularly in engines such as diesel engines. Attempts arebeing made, for example, to minimize sulfur dioxide emissions byminimizing the sulfur content of fuel oils. Although typical diesel fueloils have in the past contained 1% by weight or more of sulfur(expressed as elemental sulfur) it is now required to reduce the levelto less than 15 ppm.

The additional refining of fuels oils, necessary to achieve these lowsulfur levels, often results in a reduction in the levels of polarcomponents. In addition, refinery processes can reduce the level ofpolynuclear aromatic compounds present in such fuel oils.

Reducing the level of one or more of the sulfur, polynuclear aromatic orpolar components of diesel fuel oil can reduce the ability of the oil tolubricate the injection system of the engine. As a result of poor fuellubrication properties, the fuel injection pump of the engine may failrelatively early in the life of the engine. Failure may occur in fuelinjection systems such as high-pressure rotary distributors, in-linepumps and injectors. The problem of poor lubricity in diesel fuel oilsis likely to be exacerbated by future engine developments, aimed atfurther reducing emissions, which will result in engines having moreexacting lubricity requirements than present engines. For example, theadvent of high-pressure unit injectors increases the fuel oil lubricityrequirement. Similarly, poor lubricity can lead to wear problems inother mechanical devices dependent on the lubrication of the naturallubricity of fuel oil.

Lubricity additives for fuel oils have been described in the art. WO94/17160 describes an additive, which comprises an ester of a carboxylicacid and an alcohol, wherein the acid has from 2 to 50 carbon atoms andthe alcohol has one or more carbon atoms. Glycerol monooleate is anexample. Although general mixtures were contemplated, no specificmixtures were disclosed. While glycerol monooleate has good lubricityproperties, it is also very polar and can form emulsions with fuel andwater.

U.S. Pat. No. 3,273,981 discloses a lubricity additive that is a mixtureof A+B wherein A is a polybasic acid, or a polybasic acid ester made byreacting the acid with C₁₀₅ monohydric alcohols; while B is a partialester of a polyhydric alcohol and a fatty acid, for example glycerylmonooleate, sorbitan monooleate or pentaerythitol monooleate. Themixture finds application in jet fuels. Such high polarity fueladditives act as detergents and are only weakly soluble in fuel.

U.S. Pat. No. 6,080,212 teaches the use of two esters with differentviscosities in diesel fuel to reduce smoke emissions and increase fuellubricity.

In a preferred embodiment, methyl octadecenoate, a major component ofbiodiesel, was included in the formula. Similarly, U.S. Pat. No.5,882,364 also describes a fuel composition comprising middle distillatefuel oil and two additional lubricating components. Those componentsbeing (a) an ester of an unsaturated monocarboxylic acid and apolyhydric alcohol and (b) an ester of a polyunsaturated monocarboxylicacid and a polyhydric alcohol having at least three hydroxy groups.

The approach of using a two component lubricity additive was pioneeredin U.S. Pat. No. 4,920,691. The inventors here describe an additive anda liquid hydrocarbon fuel composition consisting essentially of a fueland a mixture of two straight chain carboxylic acid esters, one having alow molecular weight and the other having a higher molecular weight.

In U.S. Pat. No. 5,713,965, the synthesis of alkyl esters from animalfats, vegetable oils, rendered fats and restaurant grease is described.The resultant alkyl esters are reported to be useful as additives toautomotive fuels and lubricants.

Alkyl esters of fatty acids derived from vegetable oleaginous seeds wererecommended at rates between 100 to 10,000 ppm to enhance the lubricityof motor fuels in U.S. Pat. No. 5,599,358. Similarly, a fuel compositionwas disclosed in U.S. Pat. No. 5,730,029, comprising low sulfur dieselfuel and esters from the transesterification of at least one animal fator vegetable oil triglyceride.

SUMMARY OF THE DISCLOSURE

In the present disclosure, it has been found that particular additives,when combined in adventitious ratios, possess synergistic lubricantenhancing characteristics. Specifically, it has been established thatmixtures of at least two classes of compounds that can be dissolved in apetroleum distillate fuel increase the lubricity of the fuel. The firstclass of compounds possess at least one free hydrogen moiety capable ofhydrogen bonding yet have sufficiently low polarity that they formsolutions when mixed with petroleum distillate fuels at concentrationsof up to about 1% (v/v). The second class of compounds are hydrophobicfatty acid esters that are miscible with petroleum distillate fuels.

Accordingly, a fuel additive composition is disclosed which comprisesone or more hydrogen bonding compounds derived from a first long chainfatty acid, selected from a fatty acid alcohol, amine, amide, imide orDiels-Alder adduct and one or more esters of a second long chain fattyacid, wherein the hydrogen bonding compounds and the esters are solublein petroleum distillate fuels and the first and second long chain fattyacids are the same or different The fuel additive composition is addedto the fuel to decrease friction and wear that occurs in pumps, engines,motors, valves and other mechanical parts that are in contact with apetroleum distillate and are lubricated, at least in part, by thedistillate.

The combination of a hydrogen bonding compound and fatty acid estercompound have additional beneficial characteristics that increase theirefficacy in many applications. The compounds have elevated solubility inhydrocarbon fuels when compared with other lubricity-improvingadditives. This solubility property allows the additives to beintroduced into fuel at relatively high concentrations that provideadditional lubricant and combustion benefits.

The fuel additive compositions are also biodegradable and thus arerapidly decomposed in the environment. Further, the fuel additivecompositions have low solubility in water and cannot be removed from theblend by contact between distillate fuel and water.

The present disclosure also includes petroleum distillate fuelscomprising an additive composition described herein. Also included is amethod for increasing the lubricity of a petroleum distillate fuelcomprising adding a lubricating-effective amount of an additivecomposition described herein to said fuel.

Other features and advantages of the present disclosure will becomeapparent from the following detailed description. It should beunderstood, however, that the detailed description and the specificexamples while indicating preferred embodiments of the disclosure aregiven by way of illustration only, since various changes andmodifications within the spirit and scope of the disclosure will becomeapparent to those skilled in the art from this detailed description.

DETAILED DESCRIPTION OF THE DISCLOSURE Definitions

The term “fuel” as used herein refers to petroleum distillate fuelshaving sulfur content of less than or equal to 0.2% by weight.

The term “lubricating-effective amount” as used herein is a quantitysufficient to, when included in a fuel of the present disclosure, effectdesired or beneficial lubricating effects. For example, alubricating-effective amount is an amount of the additive composition ofthe present disclosure to achieve any increase in lubricity of a fuelcompared to the lubricity obtained without addition of the additivecomposition of the present disclosure.

The term “soluble” as used herein means that an effective amount of asubstance will dissolve to provide an substantially homogeneous solutionin a desired liquid.

The term “fatty acid” as used herein refers to aliphatic monocarboxylicacids, derived from, or contained in esterified form in an animal orvegetable fat, oil or wax. Natural fatty acids typically have a chain of4 to 28 carbons (usually unbranched and even numbered), which may besaturated or unsaturated.

The term “Diels Alder adduct” as used herein refers to a compoundprepared from the reaction of a diene and a dienophile (typically adouble bond-containing compound such as alkene) under Diels Alderreaction conditions.

The term “alcohol” as used herein refers to the chemical group “—OH”.

The term “amine” as used herein refers to the chemical grouping“—N(R^(a))₂”, wherein R^(a) is H, substituted or unsubstitutedC₁₋₂₀alkyl or substituted or unsubstituted aryl and each R^(a) is thesame or different.

The term “amide” as used herein refers to the chemical grouping“—C(O)N(R^(b))₂”, wherein R^(b) is H, substituted or unsubstitutedC₁₋₂₀alkyl or substituted or unsubstituted aryl and each R^(b) is thesame or different

The term “imide” as used herein refers to the chemical grouping“—C(O)—NR^(c)—C(O)—”, wherein R^(c) is H, substituted or unsubstitutedC₁₋₂₀alkyl or substituted or unsubstituted aryl.

The term “substituted” as used herein, unless otherwise indicated, meansthat the group is substituted with one to three substituentsindependently selected from halo, halo-substituted C₁₋₄alkyl, aryl,alkyl-substituted aryl and halo-substituted aryl.

The term “C_(m-n)alkyl” as used herein means straight and/or branchedchain, saturated alkyl radicals containing from “m” to “n” carbon atomsand includes (depending on the identity of m and n) methyl, ethyl,propyl, isopropyl, n-butyl, s-butyl, isobutyl, t-butyl,2,2-dimethylbutyl, n-pentyl, 2-methylpentyl, 3-methylpentyl,4-methylpentyl, n-hexyl and the like, where the variable m is an integerrepresenting the smallest number of carbon atoms in the alkyl radicaland n is an integer representing the largest number of carbon atoms inthe alkyl radical.

The term “C_(m-n)alkenyl” as used herein means straight and/or branchedchain, unsaturated alkyl radicals containing from “m” to “n” carbonatoms and one to three double bonds, and includes (depending on theidentity of m and n) vinyl, allyl, 2-methylprop-1-enyl, but-1-enyl,but-2-enyl, but-3-enyl, 2-methylbut-1-enyl, 2-methylpent-1-enyl,4-methylpent-1-enyl, 4-methylpent-2-enyl, 2-methylpent-2-enyl,4-methylpenta-1,3-dienyl, hexen-1-yl and the like, where the variable mis an integer representing the smallest number of carbon atoms in thealkenyl radical and n is an integer representing the largest number ofcarbon atoms in the alkenyl radical.

The term “C_(m-n)alkynyl” as used herein means straight and/or branchedchain, unsaturated alkyl radicals containing from “m” to “n” carbonatoms and one to three triple bonds, and includes (depending on theidentity of m and n) propargyl, but-1-ynyl, but-2-ynyl, but-3-ynyl,4-methylpent-1-ynyl, 4-methylpent-2-ynyl, hex-1-ynyl and the like, wherethe variable m is an integer representing the smallest number of carbonatoms in the alkynyl radical and n is an integer representing thelargest number of carbon atoms in the alkynyl radical.

The term “aryl” as used herein means a monocyclic, bicyclic or tricycliccarbocyclic ring system containing from 6 to 14 carbon atoms and inwhich at least one ring is aromatic and includes phenyl, naphthyl,anthracenyl, 1,2-dihydronaphthyl, 1,2,3,4-tetrahydronaphthyl, fluorenyl,indanyl, indenyl and the like.

The term “halo-substituted” as used herein means that one or all of thehydrogen atoms in the claimed radical have been replaced with a halogenatom, suitably, fluorine.

The term “alkyl-substituted” as used herein means that one or more,suitably 1 to 5, more suitably 1 to 3, of the hydrogen atoms in theclaimed radical have been replaced with a C₁₋₄alkyl group, suitably,methyl.

The term “hydroxy-substituted” as used herein means that one or more,suitably 1 to 5, more suitably 1 to 3, of the hydrogen atoms in theclaimed radical have been replaced with a hydroxy (OH) group.

The term “alkoxy-substituted” as used herein means that one or more,suitably 1 to 5, more suitably 1 to 3, of the hydrogen atoms in theclaimed radical have been replaced with a C₁₋₆alkoxy group, suitably,methoxy.

The term “halo” as used herein means halogen and includes chloro,fluoro, bromo and iodo.

Unless otherwise stated, all percentages defined herein are in units ofvolume/volume (v/v).

In understanding the scope of the present disclosure, the term“comprising” and its derivatives, as used herein, are intended to beopen ended terms that specify the presence of the stated features,elements, components, groups, integers, and/or steps, but do not excludethe presence of other unstated features, elements, components, groups,integers and/or steps. The foregoing also applies to words havingsimilar meanings such as the terms, “including”, “having” and theirderivatives. Finally, terms of degree such as “substantially”, “about”and “approximately” as used herein mean a reasonable amount of deviationof the modified term such that the end result is not significantlychanged. These terms of degree should be construed as including adeviation of at least ±5% of the modified term if this deviation wouldnot negate the meaning of the word it modifies.

Fuel Additive Compositions

In an embodiment of the present disclosure, the fuel additivecompositions comprise one or more hydrogen bonding compounds derivedfrom a first long chain fatty acid, selected from a fatty acid alcohol,amine, amide, imide or Diels-Alder adduct and one or more esters of asecond long chain fatty acid, wherein the hydrogen bonding compounds andthe esters are soluble in petroleum distillate fuels and the first andsecond long chain fatty acids are the same or different.

In a suitable embodiment of the present disclosure, the long chain fattyacids are from vegetable oils. In a subsequent embodiment of the presentdisclosure, the long chain fatty acids are from tall, soybean, canola,palm, sunflower, rapeseed, flaxseed, corn or coconut oil. In a furtherembodiment of the present disclosure, the long chain fatty acids arefrom animal fats or greases. In a subsequent embodiment, the animal fator grease is from swine, poultry and beef.

In a suitable embodiment of the present disclosure, the one or morehydrogen bonding compounds have sufficiently low polarity that they aresoluble in petroleum distillate fuels at concentrations equal to or lessthan 1% (v/v).

In another embodiment of the present disclosure, the one or morehydrogen bonding compound is an amide of the first long chain fattyacid. In a further embodiment of the present disclosure, the one or morehydrogen bonding compounds are ethanolamides of the first long chainfatty acid. The ethanolamide of the first long chain fatty acid isproduced from the reaction of ethanolamine and the first long chainfatty acid in the presence of suitable basic catalyst. In a suitableembodiment, the first long chain fatty acid is erucic acid.

In another embodiment of the present disclosure, the one or morehydrogen bonding compound is an imide derivative of the first long chainfatty acid. In a subsequent embodiment, the first long chain fatty acidcomprises a conjugated diene when the hydrogen bonding compound is animide. In a suitable embodiment, the conjugated diene is conjugatedlinoleic acid or conjugated linolenic acid. In a subsequent embodiment,the imide is produced by the Diels-Alder condensation of a maleimidederivative and the conjugated diene. In a subsequent embodiment, themaleimide derivative is an N—C₁₋₆alkyl derivative or anN-aryl-derivative. In a suitable embodiment, the N-aryl derivative isN-phenyl maleimide.

In another embodiment, the one or more hydrogen bonding compounds is apolyol ester of a long chain fatty acid. By polyol it is meant astraight-chain, branched-chain, cyclic, saturated or unsaturatedhydrocarbon compound comprising more than one hydroxyl (OH) group.Examples of polyols include, but are not limited to glycerol, ethyleneglycol, diethylene glycol, triethylene glycol and polyethylene glycol(PEG). In another embodiment, the polyol is of the formula—O(CH₂CH₂O)_(n)CH₂CH₂OH, where n is an integer from 0 to 5. Suitably nis 1.

In an embodiment of the present disclosure, the one or more hydrogenbonding compounds are selected from compounds of Formula I:

wherein R¹ is selected from C₆₋₂₄alkyl, C₆₋₂₄alkenyl and C₆₋₂₄-alkynyl,all of which are unsubstituted or substituted with one to threesubstituents independently selected from halo, halo-substitutedC₁₋₄alkyl, aryl, alkyl-substituted aryl and halo-substituted aryl, orR¹ is interrupted by one or two cyclohexyl or cyclohexenyl groups bothof which are unsubstituted or substituted with one to three substituentsindependently selected from halo, halo-substituted C₁₋₄alkyl, aryl,alkyl-substituted aryl and halo-substituted aryl or the one or twocyclohexyl or cycloyhexenyl groups are part of a bi- or tricyclic fusedring system which optionally contains an N atom in place of one to threecarbon atoms and is unsubstituted or substituted with one to threesubstituents independently selected from halo, halo-substitutedC₁₋₄alkyl, aryl, alkyl-substituted aryl and halo-substituted aryl;R₂ is selected from OC₁₋₆alkyl, O—C₁₋₆alkenyl, NHC₁₋₆alkyl,NH—C₁₋₆alkenyl, NH-hydroxy-substituted C₁₋₆alkyl,O(CH₂CH₂O)_(n)CH₂CH₂OH, O—CH₂CHOHCH₂OH; andn is an integer from 0 to 5,provided that at least one of R¹ and R² contains a hydrogen atom that isfree to participate in a hydrogen bond.

It is an embodiment of the disclosure R¹ is selected from C₆₋₂₄alkyl andC₆₋₂₄alkenyl, both of which are unsubstituted or substituted with one totwo substituents independently selected from halo, halo-substitutedC₁₋₄alkyl, phenyl, alkyl-substituted phenyl and halo-substituted phenyl,or

R¹ is interrupted by one or two cyclohexyl or cyclohexenyl groups bothof which are unsubstituted or substituted with one to two substituentsindependently selected from halo, halo-substituted C₁₋₄alkyl, phenyl,alkyl-substituted phenyl and halo-substituted phenyl or the one or twocyclohexyl or cyclohexenyl groups are part of a bi- or tricyclic fusedring system which optionally contains an N atom in place of one carbonatom and is unsubstituted or substituted with one to two substituentsindependently selected from halo, halo-substituted C₁₋₄alkyl, phenyl,alkyl-substituted phenyl and halo-substituted phenyl.

In another embodiment, R₂ is selected from OC₁₋₄alkyl, O—C₁₋₄alkenyl,NHC₁₋₄alkyl, NH—C₁₋₄alkenyl, NH-hydroxy-substituted C₁₋₄alkyl,O(CH₂CH₂O)_(n)CH₂CH₂OH, O—CH₂CHOHCH₂OH, and n is an integer from 0 to 3.

In particularly suitable embodiments of the present disclosure, the oneor more hydrogen bonding compounds are selected from

In a suitable embodiment of the disclosure, the one or more hydrogenbonding compounds are present in the fuel additive composition in anamount from 1 to 99 percent by weight of the fuel additive. In anotherembodiment, the hydrogen bonding compound in the additive is included at50% by weight of the additive. In another embodiment the hydrogenbonding compound in the additive is included at 10 percent by weight ofthe additive.

In an embodiment of the present disclosure, the one or more esters of asecond long chain fatty acid are miscible with petroleum distillatefuels or have solubility of at least 5 percent in petroleum distillatefuels. In a subsequent embodiment, the one or more esters of a secondlong chain fatty acid are soluble in petroleum distillate fuelscomprising the hydrogen bonding compounds.

In an embodiment of the disclosure, the second long chain fatty acid isfrom a vegetable oil or animal fat.

In another embodiment, the vegetable oil is tall, soybean, canola, palm,sunflower, rapeseed, flaxseed, corn, mustard seed, safflower, crambe orcoconut oil.

In a suitable embodiment of the present disclosure, the second longchain fatty acid is from canola oil.

In another embodiment of the present disclosure, the one or more estersof a second long chain fatty acid are C₁₋₆alkyl esters of the secondlong chain fatty acid. In a specific embodiment, the one or moreC₁₋₆alkyl esters are methyl esters. In a subsequent embodiment, the oneor more esters of a second long chain fatty acid are aryl esters of thesecond long chain fatty acid.

In another embodiment, the one or more esters of a second long chainfatty acid also comprise an ether in the ester moiety. In a subsequentembodiment, the ether group is a monoalkoxy ether derived from a glycol.In a specific embodiment of the present disclosure, the monoalkoxy etheris methoxy-2-propyl alcohol.

In another embodiment of the present disclosure, the one or more estersof a second long chain fatty acid are a cellosolve (OCH₂CH₂OR,R═C₁₋₆alkyl) ester of the second long chain fatty acid. In a specificembodiment, the cellosolve ester is butyl cellosolve(OCH₂CH₂OCH₂CH₂CH₂CH₃).

In another embodiment of the present disclosure the esters of a secondlong chain fatty acid are carboxylic acid esters of a propylene etherand the second long chain fatty acid.

In a further embodiment, the one or more esters of a second long chainfatty acid are carboxylic acid esters of a polyether and the second longchain fatty acid. In specific embodiments, the polyether is a monoalkylether substituted polyethylene glycol or a monoalkyl ether substitutedpolypropylene glycol where the glycol mass is less than 600 daltons.

In another embodiment of the present disclosure, the one or more estersof a second long chain fatty acid are the methoxy-2-propyl ester of afatty acid from canola oil.

In an embodiment of the present disclosure, the one or more esters of asecond long chain fatty acid are selected from compounds of Formula II:

R³ is selected from C₆₋₂₄alkyl, C₆₋₂₄alkenyl and C₆₋₂₄-alkynyl, all ofwhich are unsubstituted or substituted with one to three substituentsindependently selected from halo, halo-substituted C₁₋₄alkyl, aryl,alkyl-substituted aryl and halo-substituted aryl; andR⁴ is selected from C₁₋₆alkyl, C₁₋₆alkenyl, halo-substituted C₁₋₆alkyl,hydroxy-substituted C₁₋₆alkyl, alkoxy-substituted C₁₋₆alkyl, aryl,hydroxy-substituted aryl, alkoxy-substituted aryl, halo-substituted aryland polyethers.

In an embodiment of the disclosure, R³ is selected from C₆₋₂₄alkyl andC₆₋₂₄alkenyl, both of which are unsubstituted or substituted with one totwo substituents independently selected from halo, halo-substitutedC₁₋₄alkyl, phenyl, alkyl-substituted phenyl and halo-substituted phenyl.

In another embodiment of the disclosure, R⁴ is selected from C₁₋₄alkyl,C₁₋₄alkenyl, halo-substituted C₁₋₄alkyl, hydroxy-substituted C₁₋₄alkyl,alkoxy-substituted C₁₋₄alkyl, phenyl, hydroxy-substituted phenyl,alkoxy-substituted phenyl, halo-substituted phenyl and polyethers.

In a particular embodiment of the present disclosure, the one or moreester-containing compounds have the following structure:

In a suitable embodiment of the disclosure, the one or more esters of asecond long chain fatty acid are present in the fuel additivecomposition in an amount from 1 to 99 percent by weight of the fueladditive. In another embodiment the ester containing compound is 50percent of the weight of the additive. In another embodiment the esteris 90 percent of the weight of the additive.

In another embodiment of the present disclosure, the fuel additivecompositions gain additional benefit by the addition of a solvent thatalso contains an ether. In a subsequent embodiment, an ether is added asa third component to the fuel additive, the ether characterized in thatit can specifically lower the freezing point, cloud point and/or pourpint of the fuel additive. In a specific embodiment of the presentdisclosure, methyl tertiary butyl ether (MTBE) is added to the one ormore esters of a second long chain fatty acid.

In an embodiment of the present disclosure the one or more esters of asecond long chain fatty acid have a cloud point of about −15° C. toabout −20° C., suitably about −18° C., and a pour point of about −25° C.to about −30° C., suitably about −27° C. In a further embodiment, theone or more esters of a second long chain fatty acid in combination witha solvent has a cloud point of about −20° C. to about −30° C., suitablyabout −21° C. to about −24° C., and a pour point of about −30° C. toabout −50° C., suitably about −36° C. to about −45° C. The lowtemperature properties of the ether-containing additive and solventallow the use of the additive at lower temperatures.

In a suitable embodiment, the fuel additive compositions also comprise adetergent.

In further embodiments of the present disclosure, the petroleumdistillate fuel is gasoline, diesel, jet, kerosene, biodiesel, propaneor ethanol containing fuel for gasoline engines.

The present disclosure also includes petroleum distillate fuelscomprising an additive composition described herein. In an embodiment,the fuel comprises a lubricating effective amount of an additivecomposition disclosed herein. In a further embodiment, the fuelcomprises from about 0.01% to about 5% (v/v), suitably from about 0.05%to about 0.2% (v/v), of an additive composition of the presentdisclosure.

Also included is a method for increasing the lubricity of a petroleumdistillate fuel comprising adding a lubricating-effective amount of anadditive composition described herein to said fuel.

The following non-limiting examples are illustrative of the presentdisclosure:

EXAMPLES Materials and Methods Cold Flow Properties Measurements:

Cold flow properties were measured using a refrigerated bath(Serial#90FMS33990-1, Neslab Instruments, Inc., Newington, N.H., USA)which is circulated with ethylene glycol. Between 15 and 25 mL of estersample was placed into a glass test tube which measures 26 mm indiameter. The test tube containing the sample was then put into a 100 mlvolumetric cylinder which was placed deep into the refrigerated bath.The experimental settings and measurement procedures largely followedthose of standard method ASTM D97. At every 3° C. of cooling, the sampleis inspected. The cloud point is determined by visually inspecting for ahaze in the sample. Pour point is determined by adding 3° C. to thetemperature at which no sample movement is detected after the glass tubeis tilted for five seconds.

Lubricity Analysis on the m-ROCLE:

Lubricity is measured using a Munson Roller On Cylinder LubricityEvaluator (M-ROCLE; Munson, J. W., Hertz, P. B., Dalai, A. K. andReaney, M. J. T. Lubricity survey of low-level biodiesel fuel additivesusing the “Munson ROCLE” bench test, SAE paper 1999-01-3590). TheM-ROCLE test apparatus conditions are given in Table 1. During the test,the reaction torque was proportional to the friction force produced bythe rubbing surfaces and was recorded by a computer data acquisitionsystem. The recorded reaction torque was used to calculate thecoefficient of friction with the test fuel. Each wear scar produced iselliptical in shape. Major and minor axes are measured at 100 timesmagnification through a microscope. The wear scar area is calculatedfrom the formula for an ellipse. After determining the unlubricatedHertzian contact stress, a dimensionless lubricity number (LN),indicating the lubricating property of the test fuel, was determinedusing the following equation:

${L\; N} = \frac{\sigma_{SS}}{\sigma_{H} \times \mu_{SS}}$ andσ_(SS) = P/A

where σ_(SS) is the steady state ROCLE contact stress (MPa), σ_(H) isthe Hertzian theoretical elastic contact stress (MPa), μ_(SS) is thesteady state coefficient of friction, P is the applied load (N) and A isthe roller scar area (m²).

The reference or base fuel used was pre-production, unadditized ultralow sulphur diesel fuel (containing less than 15 ppm sulphur), which wasprovided by Alberta Research Council (Alberta, Canada). Each fuel estersample was lubricity tested six times on the machine followed by acalibration of the reaction torque.

Example 1 Two Stage Interesterification of Canola Based Methyl Esterwith 1-methoxy-2-propanol and Potassium Methylate Catalyst

Alcohol ether enriched esters were prepared using a two-stage basecatalysed alcoholysis process. The two-stage reaction was required toprogressively remove a great majority of methyl group from the methylester and exchange it with an acyl group from 1-methoxy-2-propanolalcohol. A 1.2:1 molar ratio of 1-methoxy-2-propanol to methyl ester wasused. In the first stage reaction, 20 mL methyl ester was reacted with6.99 mL 1-methoxy-2-propanol (>99.5%, ReagentPlus, Dow Chemical) and0.56 mL of potassium methylate catalyst (BASF Chemical Company). Thecatalyst solution contains approximately 30% (w/w) of potassiummethylate in methanol. The reaction was carried out at 85-90° C. for1.25 hour in a 40 mL test tube. Nitrogen was distributed to the reactionmedia in order to facilitate removal of the methanol produced and toassist agitation. In the second stage reaction, 6.99 mL1-methoxy-2-propanol and 0.56 mL of potassium methylate catalyst wasadded to the reaction media. The reaction was carried out at 85-90° C.for 1.25 hour in a 40 mL test tube. The reaction media was thenneutralized with hydrochloric acid solution followed by water wash toremove residual catalysts and excess 1-methoxy-2-propanol. The purifiedesters were analysed for conversion rate by 1H Nuclear MagneticResonance Spectroscopy method (Univ. of Saskatchewan, SK, Canada).

The resulting esters contained approximately 85% alcohol ether and 15%un-converted methyl ester. The product had a cloud point at −18° C. anda pour point of −27° C., which are significantly below the cloud point(−12° C.) and pour point (−12° C.) recorded for the starting methylester.

Example 2 Three Stage Interesterification of Canola Based Methyl Esterwith 1-methoxy-2-propanol and Potassium Methylate and Metal SodiumCatalysts

All processes and conditions for the first two-stage reactions wereidentical to those described in Example 1. An alternate base catalystwas used in the third stage reaction. Approximately 0.05 grams offreshly cut metal sodium was first dissolved in 4 mL1-methoxy-2-propanol. The catalyst solution was then added to thereaction media. The third stage reaction was carried out at 85-90° C.for 1.5 hour. Again, nitrogen source was introduced to the reactionmedia to assist the agitation and the removal of the forming methanol.The resulting esters were neutralized and purified following identicalprocedures described in Example 1.

The resulting esters contained approximately 91% alcohol ether and 9%un-converted methyl ester. The product had a cloud point at −18° C. anda pour point of −27° C., which are significantly below the cloud point(−12° C.) and pour point (−12° C.) recorded for the starting methylester.

A three-stage interesterification reaction results in more consistentand higher methyl ester to alcohol ether conversion rates. Although anincrease of conversion rate from 85 to 91% did not lead to furtherimprovement on cloud and pour point.

Example 3 Improvement of Cloud and Pour Point by the Addition of anEther Solvent

Addition of an ether solvent such as MTBE (tert-Butyl methyl ether,99+%, A.C.S. reagent, Sigma) to the alcohol ether samples produced inExample 1 and Example 2 at 15% v/v (volume of MTBE over volume ofMTBE+alcohol ether), lowered cloud points from −18° C. to between −21and −24° C., and pour points from −27° C. to between −36 and −45° C.

Example 4 Production of Diels-Alder Adduct of N-Phenyl Maleimide andConjugated Linoleic Acid

Ethyl cis, trans-conjugated linoleate made from safflower oil (Reaney etal. U.S. Pat. No. 6,822,104 B2) was isomerized to ethyltrans,trans-linoleate catalyzed by iodine (5% mole ratio; IDESES, R.; A.SHAM. Study of the radical mechanism of iodine-catalized isomerizationof conjugated diene systems. J. Am. Oil Chem. Soc., 1989. 66(7): p.948-952). It was found that the protons attached to conjugated doublebonds of cis, trans-linoleate found at 6.31, 5.96, 5.68, 5.31 ppm weregreatly diminished and that new signals attributable to ethyl trans,trans-linoleate had appeared at 6.02 and 5.58 ppm. The resulting ethyltrans, trans-linoleate was diluted with dichloromethane and mixed wellwith N-phenyl maleimide and then the dichloromethane was removed byrotary evaporator. The reaction was conducted at 60° C. for 24 hoursunder N₂ atmosphere. The crude Diels-Alder adduct was formed andpurified using silica chromatography with solvent system of 10% ethylacetate in hexane. The Diels-Alder adduct was identified by new ¹H NMRsignals at 5.83 (s) and 3.27 ppm and the peaks for protons at theconjugated double bonds of ethyl conjugated linoleate disappeared. Inaddition, mass spectrometry (EI) also gave the correct molecular weightof 481.3205 for the Diels-Alder adduct of N-phenyl maleimide and ethylconjugated linoleate.

Example 5

m-ROCLE Lubricity Analysis of Diesel Fuel Containing methoxy-2-propanolEsters from Example 2

Lubricity was measured using a Munson Roller On Cylinder LubricityEvaluator (M-ROCLE; Munson, J. W., Hertz, P. B., Dalai, A. K. andReaney, M. J. T. Lubricity survey of low-level biodiesel fuel additivesusing the “Munson ROCLE” bench test, SAE paper 1999-01-3590). TheM-ROCLE test apparatus conditions are given in Table 1. M-ROCLEoperation and equations used to describe lubricity number are describedabove.

A total of 6 replications were performed to allow for statisticalanalysis. All tests were performed on a 1% solution of concentrate ordistillate in kerosene. Table 2 contains the results of analyses.

In testing it was found that lubricity numbers of the reference ultralow sulphur diesel (ULSD) fuel were significantly improved when it wasincorporated with 1% alcohol ethers. Addition of methoxy-2-propanolester of example 2 to the diesel fuel also reduced wear scar area and tolesser extent coefficient of friction.

Example 6

m-ROCLE Lubricity Analysis of Pre-Production Diesel Fuel Containingmethoxy-2-propanol Esters from Example 2

Lubricity measurements for pre-production ultra low sulfur diesel fuel(ULSD & 100 ppm acylethanolamides containing methoxy-2-propanol esterfrom Example 2 additives were performed as described in Example 5. Itwas found that lubricity numbers of the pre-production ULSD wereimproved when it was incorporated with 0.1% methoxy-2-propanol ester ofExample 2 (Table 3). Wear scar areas were also reduced as a result ofthe combined additives. Thus the combination of the additivesacylethanolamide and methoxy-2-propanol ester of Example 2 providessynergistic lubricant enhancing characteristics. This quality trait hasnot been previously reported. It was noted that methoxy-2-propanol esterof Example 2 addition from 0.1 to 0.2% did not result in furtherimprovement in lubricity properties.

Example 7 m-ROCLE Lubricity Analysis of Pre-Production Diesel FuelContaining methoxy-2-propanol Esters from Example 2 Combined with MTBE

Lubricity measurement for the pre-production ultra low sulfur dieselfuel (ULSD & 100 ppm acylethanolamide; AEA) combined with MTBE andmethoxy-2-propanol ester of Example 2 were performed as described inExample 5. It was found that addition of MTBE at 0.05% improvedlubricity characteristics of the pre-production ULSD. However thecombined additives of MTBE and methoxy-2-propanol ester of Example 2 atcurrent levels (Table 4) did not show a synergistic lubricant enhancingeffect.

Example 8 HFRR Lubricity Analysis of Diesel Fuel Combined withmethoxy-2-propanol Ester of Example 2

The High Frequency Reciprocating Rig or HFRR has been the most widelyused lubricity bench test. These tests are conducted according tostandard methods (CEC F-06-A-96. Measurement of Diesel FuelLubricity—Approved Test Method. HFRR Fuel Lubricity Test.)

The HFRR results are summarized in Table 5 and Table 6. They werecompared to the results obtained by the m-ROCLE method (Table 3 and 4).Trends in lubricity improvement due to the addition ofmethoxy-2-propanol ester of Example 2 were similar from both m-ROCLE(Table 3) and HFRR (Table 5) methods. The improvement in lubricity wasillustrated by reduction in wear scar diameters and its component majorand minor axes. Combined additions of methoxy-2-propanol ester ofExample 2 and MTBE to the pre-production commercial ULSD resulted infurther reduction in major and minor axis and subsequent wear scardiameters (compare Tables 4 and 6).

Example 9 Isolation and its Structure Analysis of a Lubricity Additivein Diesel Fuel

Diesel (500 mL) from a Canadian supplier (Bus Grade, Dec. 7, 2006) waspoured into a column with packed dry silica gel (40 g). First, 150 mL ofthe diesel fraction after passing through dry silica gel was used forthe lubricity tests. Once the diesel sample passed through silica geland the more polar compounds were absorbed onto silica gel, hexane (100mL) was used to elute less polar compounds. Subsequently, increasingpolarity solvent systems: 5% EtOAc in hexane (250 mL, F1), 20% EtOAc inhexane (250 mL, F2), 50% EtOAc in hexane (250 mL, F3) and 20% MeOH indichloromethane (250 mL, F4), were used to obtain four fractions (F1-F4)and to prepare proton-NMR samples for analysis. From proton NMR(Jia-01-161(9)), fraction 4 contained the lubricant additive with traceimpurity and was purified further by preparative TLC with developingsolvent: 5% MeOH in dichloromethane (developed 3×). Pure compound (32.0mg, 78 ppm) was obtained and prepared for spectral analysis including(¹H, COSY, APT, ¹³C, IR). Based on NMR and IR spectra analysis, thestructure of the compound was R—OCH₂CH₂OCH₂CH₂OH(R=FATTY ACIDS of whichthe majority were oleic and linoleic acid from GC analysis). Thelubricity of the diesel fuel with no additive was very poor. HFRR testsshowed this fuel a large wear scar of 730 microns in diameter. Additionof the methoxy-2-propyl esters of fatty acids to this diesel fuelimproved the HFRR wear scar by reducing it to 700 microns in diameter.The commercial diesel containing the hydrogen bonding lubricity additivealone produced a significant reduction in wear scar area. The wear scarwas just 590 microns. Surprisingly fuels that contained both additives(methoxy-2-propyl esters and H-bonding additive) had greatly reducedwear scars of just 500 microns.

While the present disclosure has been described with reference to whatare presently considered to be the preferred examples, it is to beunderstood that the disclosure is not limited to the disclosed examples.To the contrary, the disclosure is intended to cover variousmodifications and equivalent arrangements included within the spirit andscope of the appended claims.

All publications, patents and patent applications are hereinincorporated by reference in their entirety to the same extent as ifeach individual publication, patent or patent application wasspecifically and individually indicated to be incorporated by referencein its entirety. Where a term in the present application is found to bedefined differently in a document incorporated herein by reference, thedefinition provided herein is to serve as the definition for the term.

TABLE 1 M-ROCLE TEST CONDITIONS Fuel temperature, ° C. 25 ± 1.5 Fuelcapacity, mL 63 Ambient temperature, ° C. 24 ± 1.0 Ambient humidity, %35-45 Applied load, N 24.6 Load application velocity, mm/s 0.25 Testduration, min 3 Race rotational velocity, rpm 600 Race Surface velocity,m/s 1.10 Test specimens Falex test cylinder, F-S25 test rings, SAE 4620steel Outer diameter, mm 35.0 Width, mm 8.5 Falex tapered test rollers,F-15500, SAE 4719 steel Outer diameter, mm 10.18, 10.74 Width, mm 14.80

TABLE 2 LUBRICITY DATA OF DIESEL FUEL CONTAINING METHOXY-2-PROPANOLESTERS Lubricity Wear Scar Standard Coefficient Number Standard Area (n= 6) Deviation of Friction Standard Samples (n = 6) Deviation (mm²)(mm²) (n = 6) Deviation 100% Ultra Low 0.622 0.048 0.360 0.022 0.1230.005 Sulphur Diesel Fuel (reference) 99% Ultra Low 0.971 0.034 0.2550.009 0.110 0.001 Diesel Fuel, 1% methoxy-2-propyl ester of Example 299% Ultra Low 0.938 0.066 0.250 0.017 0.117 0.001 Diesel Fuel, 1%methoxy-2-propyl ester of Example 2

TABLE 3 Lubricity Characteristics of Pre-production Ultra Low SulfurDiesel Fuel Containing 100 ppm Acylethanolamide (AEA) and Various LevelsOf Methoxy-2-propyl Ester of Example 2 Lubricity Wear Scar StandardCoefficient Number Standard Area (n = 6) Deviation of Friction StandardSamples (n = 6) Deviation (mm²) (mm²) (n = 6) Deviation ULSD 0.622 0.0480.360 0.022 0.123 0.005 ULSD & 0.758 0.028 0.307 0.011 0.117 0.001 100ppm AEA ULSD & 0.892 0.038 0.270 0.013 0.114 0.002 100 ppm AEA & 0.1%methoxy- 2-propyl ester of Example 2 ULSD & 0.899 0.038 0.261 0.0100.117 0.002 100 ppm AEA & 0.2% methoxy- 2-propyl ester of Example 2

TABLE 4 EFFECT OF MTBE ON LUBRICITY CHARACTERISTICS OF PRE-PRODUCTIONULTRA LOW SULPHUR DIESEL FUEL COMBINED WITH 100 PPM AEA AND VARIOUSLEVELS OF METHOXY-2-PROPYL ESTER OF EXAMPLE 2 Lubricity Wear ScarStandard Coefficient Number Standard Area (n = 6) Deviation of FrictionStandard Samples (n = 6) Deviation (mm²) (mm²) (n = 6) Deviation ULSD &100 ppm 0.758 0.028 0.307 0.011 0.117 0.001 AEA ULSD & 100 ppm 0.7930.040 0.297 0.013 0.116 0.001 AEA & 0.025% MTBE ULSD & 100 ppm 0.8800.048 0.262 0.014 0.119 0.001 AEA & 0.05% MTBE ULSD & 100 ppm 0.8480.033 0.283 0.010 0.114 0.001 AEA & 0.025% MTBE & 0.075%methoxy-2-propyl ester of Example 2 ULSD & 100 ppm 0.893 0.028 0.2720.008 0.113 0.001 AEA & 0.05% MTBE & 0.15% methoxy-2-propyl ester ofExample 2

TABLE 5 LUBRICITY CHARACTERISTICS OF PRE-PRODUCTION ULTRA LOW SULFURDIESEL FUEL COMBINED WITH AEA (100 PPM) AND VARIOUS LEVELS OFMETHOXY-2-PROPYL ESTER OF EXAMPLE 2 BY HFRR METHOD Wear Major Minor ScarAxis Axis Diameter Samples (mm) (mm) (mm) ULSD 0.74 0.72 0.73 ULSD & 100ppm AEA 0.62 0.55 0.59 ULSD & 100 ppm AEA & 0.1% 0.52 0.48 0.50methoxy-2-propyl ester of Example 2 ULSD & 100 ppm AEA & 0.2% 0.54 0.470.50 methoxy-2-propyl ester of Example 2

TABLE 6 Effect of MTBE On Lubricity Characteristics of Pre-ProductionUltra Low Sulphur Diesel Fuel Combined With 100 ppm AEA and VariousLevels Of Methoxy-2-propyl Ester of Example 2 by HFRR Method Wear MajorMinor Scar Axis Axis Diameter Samples (mm) (mm) (mm) ULSD & 100 ppm AEA0.62 0.55 0.59 ULSD & 100 ppm AEA & 0.69 0.64 0.66 0.025% MTBE ULSD &100 ppm AEA & 0.58 0.54 0.56 0.05% MTBE ULSD & 100 ppm AEA & 0.56 0.500.53 0.025% MTBE & 0.075% methoxy-2-propyl Ester of example 2 ULSD & 100ppm AEA & 0.51 0.44 0.48 0.05% MTBE & 0.15% methoxy-2-propyl ester ofExample 2

We claim:
 1. A fuel additive composition comprising one or more hydrogen bonding compounds derived from a first long chain fatty acid, selected from a fatty acid alcohol, amine, amide, imide or Diels-Alder adduct and one or more esters of a second long chain fatty acid, wherein the hydrogen bonding compounds and the esters are soluble in petroleum distillate fuels and the first and second long chain fatty acids are the same or different.
 2. The composition according to claim 1, wherein the first long chain fatty acid is from a vegetable oil or animal fat.
 3. The composition according to claim 1, wherein the one or more hydrogen bonding compounds are amine derivatives of the first long chain fatty acid.
 4. The composition according to claim 1, wherein the one or more hydrogen bonding compounds are amide derivatives of the first long chain fatty acid.
 5. The composition according to claim 1, wherein the imide is produced by the Diels-Alder reaction of a maleimide derivative and the conjugated diene.
 6. The composition according to claim 5, wherein the maleimide derivative is an N—C₁₋₆alkyl derivative.
 7. The composition according to claim 6, wherein the maleimide derivative is an N-aryl derivative.
 8. The composition according to claim 1, wherein the one or more hydrogen bonding compounds are esters of a long chain conjugated fatty acid and a polyol.
 9. The composition according to claim 1, wherein the one or more hydrogen bonding compounds are selected from compounds of Formula I:

wherein R¹ is selected from C₆₋₂₄alkyl, C₆₋₂₄alkenyl and C₆₋₂₄-alkynyl, all of which are unsubstituted or substituted with one to three substituents independently selected from halo, halo-substituted C₁₋₄alkyl, aryl, alkyl-substituted aryl and halo-substituted aryl, or R¹ is interrupted by one or two cyclohexyl or cyclohexenyl groups both of which are unsubstituted or substituted with one to three substituents independently selected from halo, halo-substituted C₁₋₄alkyl, aryl, alkyl-substituted aryl and halo-substituted aryl or the one or two cyclohexyl or cycloyhexenyl groups are part of a bi- or tricyclic fused ring system which optionally contains an N atom in place of one to three carbon atoms and is unsubstituted or substituted with one to three substituents independently selected from halo, halo-substituted C₁₋₄alkyl, aryl, alkyl-substituted aryl and halo-substituted aryl; R₂ is selected from OC₁₋₆alkyl, O—C₁₋₆alkenyl, NHC₁₋₆alkyl, NH—C₁₋₆alkenyl, NH-hydroxy-substituted C₁₋₆alkyl, OCH₂CHOHCH₂OH, O(CH₂CH₂O)_(n)CH₂CH₂OH; and n is an integer from 0 to 5, provided that at least one of R¹ and R² contains a hydrogen atom that is free to participate in a hydrogen bond.
 10. The composition according to claim 9, wherein the one or more compounds of Formula I are selected from:


11. The composition according to claim 1, wherein the second long chain fatty acid is from a vegetable oil or animal fat.
 12. The composition according to claim 11, wherein the one or more esters of a second long chain fatty acid are C₁₋₆alkyl esters of the second long chain fatty acid.
 13. The composition according to claim 11, wherein the esters of a second long chain fatty acid are aryl esters of the second long chain fatty acid.
 14. The composition according to claim 11, wherein the esters of a second long chain fatty acid are cellosolve esters of the second long chain fatty acid.
 15. The composition according to claim 11, wherein the esters of a second long chain fatty acid are carboxylic acid esters of a propylene ether and the second long chain fatty acid.
 16. The composition according to claim 11, wherein the one or more esters of a second long chain fatty acid are selected from compounds of Formula II:

R³ is selected from C₆₋₂₄alkyl, C₆₋₂₄alkenyl and C₆₋₂₄-alkynyl, all of which are unsubstituted or substituted with one to three substituents independently selected from halo, halo-substituted C₁₋₄alkyl, aryl, alkyl-substituted aryl and halo-substituted aryl; and R⁴ is selected from C₁₋₆alkyl, C₁₋₆alkenyl, halo-substituted C₁₋₆alkyl, hydroxy-substituted C₁₋₆alkyl, alkoxy-substituted C₁₋₆alkyl, aryl, hydroxy-substituted aryl, alkoxy-substituted aryl, halo-substituted aryl and polyethers.
 17. The composition according to claim 16 wherein the compound of Formula II is


18. A petroleum distillate fuel comprising the additive according to claim
 1. 19. The fuel according to claim 18, wherein petroleum distillate fuel is selected from gasoline, diesel fuel, jet fuel, kerosene, biodiesel fuel, propane and ethanol containing fuel for gasoline engines.
 20. A method for increasing the lubricity of a petroleum distillate fuel comprising adding a lubricating-effective amount of an additive composition according to claim 1 to said fuel. 